in his manual he explains shortly how to impression Medeco and Emhart locks. I tried once or twice but never succeed cause I was short of blanks (we did'nt have them a lot over here at this time)

in fact you impression and file down in the normal way till you are on the shear line with one pin (the plug will turn slighly)... at this moment you file down slowly paying attention to the tiny angled marks which will appear ... (when you're on the shear line the side bar is locked up so you can "angle" your cut)

and so on on each pin till it opens

it is not really important to be really accurate with the pin angle cause there is a lot of game between two angles ... at this point you can "rattle" the blank to try to open the lock

easy in theory ... much more less in practice ... but I don't have a lot of practice on these locks

Medecopen:"I cant wait to do this... I remember over 20 years ago as a kid having a locksmith make me a key for my 67 cougar...Never seen or heard of making keys like that again until I read this thread.. I started doubting what I saw, I e mentioned it to other folks and they just looked at me weirded but they were not lock people...Is this possible on locks with side bars?"

There is an obscure technique for impressioning keys to older GM cars (6-wafer, side bar locks; single-sided keys). I remember doing it a couple times; but there were just too many other , more practical ways for fitting keys to these cars.

As far as impressioning GM side bar locks, the only real success I have ever has is on the old "in the dash" locks. If they have a little wear on them they mark pretty good. Have had about 80% success rate for those, so I always try that first. (guess I shoud have put this in automotive).

What is impressioning? The art of breaking off key blanks, or as you gain more skill, the art of filing said blanks too deeply to work in a lock. This is accompanied by practicing your patience, increasing fluency in cursing in a variety of languages and improving your aim at the round filing cabinet - all while eating through your blank supply.

Gordon

Just when you think you've learned it all, that is when you find you haven't learned anything yet.